Strain driven monoclinic distortion of ultrathin CoO films in the exchange-coupled CoO/FePt/Pt(0 0 1) system

Anne D Lamirand, Márcio M Soares, Maurizio De Santis, Aline Y Ramos, Stéphane Grenier, Hélio C N Tolentino
2015 Journal of Physics: Condensed Matter  
The structure and strain of ultrathin CoO films grown on a Pt(001) substrate and on a ferromagnetic PtFe pseudomorphic layer on Pt(001) have been determined with insitu and real time surface x-ray diffraction. The films grow epitaxially on both surfaces with an in-plane hexagonal pattern that yields a pseudo-cubic CoO(111) surface. A refined x-ray diffraction analysis reveals a slight monoclinic distortion at RT induced by the anisotropic stress at the interface. The tetragonal contribution to
more » ... he distortion results in a ratio c/a > 1, opposite to that found in the low temperature bulk CoO phase. This distortion leads to a stable Co2+ spin configuration within the plane of the film.
doi:10.1088/0953-8984/27/8/085001 pmid:25604708 fatcat:j7rqi6k36jbtrjvy2xqkzdy6ue